A Star “insider” says, “Katherine’s always complaining about having to stand outside in the cold for long periods of time, and Sofia can’t stand her whining… Finally, Sofia told her to be grateful that she has the role in the first place. That clearly didn’t go over well.”

Unfortunately, Star‘s dish is even colder than the temperature on the film’s New York set.

A source close to Vergara assures Gossip Cop the feud is “not true.” And a production source notes Vergara and Heigl worked together only ONE day – and that was two weeks ago.